Prev: Archie
Next: Input rectifier cap
From: Torben �gidius Mogensen on 9 Jun 2010 04:07
Andrew Reilly <areilly---(a)bigpond.net.au> writes:


> Back in '87 or so I had an Acorn RISC "PC", which had an ARM-2, and a "PC
> emulator".

That must have been the Archimedes A310. The RISC PC did not come out
until some time in the 90's, and this used an ARM610.

> It simulated an 8088 and the PC's basic hardware well enough
> that I was able to use it to run a "scientific" word processor to write
> my undergraduate thesis. The "feel" was about as fast as an original
> 4.77MHz PC, but I didn't run any benchmarks. I'm fairly sure that it
> would have been a straight interpreter: the machine didn't really have
> enough RAM to be mucking about with JIT compilation.

It was, indeed, an interpreter, but of the 80186 instruction set. File
transfers etc. were a lot faster than on a 4.77MHz PC, but a few things
were a bit slower. The overall speed was fine for running the
occasional DOS application (I used it mostly for games), but for serious
work, you would use native applications.

> This on a chip with no cache, no 16-bit memory operations, and which
> ran the processor clock at 4MHz or 8MHz depending on whether the
> DRAM-fetch in progress at the time was in-page or doing a row
> access...
>
> I thought it was quite a spectacular achievement.

Indeed it was. Nowadays, you would use a JIT (similar to Digital's
fx!32), so the speed would be better. ARM uses arithmetic flags similar
to x86, so it is easier for ARM to emulate x86 efficiently than it is
for, say, MIPS to do so.

Torben
From: Richard Torrens (News) on 9 Jun 2010 11:34
In article <878o9hF9o4U1(a)mid.individual.net>,
Andrew Reilly <areilly---(a)bigpond.net.au> wrote:
> Back in '87 or so I had an Acorn RISC "PC", which had an ARM-2, and a
> "PC emulator". It simulated an 8088 and the PC's basic hardware well
> enough that I was able to use it to run a "scientific" word processor
> to write my undergraduate thesis. The "feel" was about as fast as an
> original 4.77MHz PC, but I didn't run any benchmarks. I'm fairly sure
> that it would have been a straight interpreter: the machine didn't
> really have enough RAM to be mucking about with JIT compilation. This
> on a chip with no cache, no 16-bit memory operations, and which ran the
> processor clock at 4MHz or 8MHz depending on whether the DRAM-fetch in
> progress at the time was in-page or doing a row access...

> I thought it was quite a spectacular achievement.

There were also second processor cards - one of which was a PC card.

Acorn were doing significant work on multiple-processor use. In fact at
that time, Acorn in many ways were world-leaders.

--
------------------------------------------------------------------
Richard Torrens. News email address is valid - for a limited time only.
http://www.Torrens.org.uk for genealogy, natural history, wild food, walks, cats
and more!
From: Skybuck Flying on 10 Jun 2010 21:34

"nik Simpson" <nik_s(a)knology.net> wrote in message
news:ec6f5$4c113452$4b4ca99b$27619(a)KNOLOGY.NET...
> On 6/10/2010 12:15 AM, Dave Platt wrote:
>
>>
>> [And, for crying out loud, Steve Jobs did *not* invent cellphones or
>> WiFi, and I don't know of any evidence to suggest that the
>> availability of the iPhone has increased cell-phone usage above what
>> it would have been if the iPhone had never existed. You really ought
>> to have a good reason to issue oaths of damnation against somebody!]
>>
>
> Given the well documented problems of the iPhone on AT&T's network, it may
> have even reduced the number of calls, well completed calls anyway ;-)

Yeah good point as well..

Bad wireless/mobile phone service might actually cause lives to be lost...

Instead of trying to get the damn mobile phone working, which ofcourse
fails...

One could have gone to the nearest real phone and get some decent service
and save lifes ! ;)

Bye,
Skybuck =D


 | 
Pages: 1
Prev: Archie
Next: Input rectifier cap